Last fall Matt Foti‘s excellent crew moved a mature Katsura tree (Cercidiphyllum japonicum) on the UMass campus in Amherst. Jim Flott showed one photo of the tree in his New England Grows presentation last week, to illustrate the breadth of a root mass; take a look here to see what it looked like during and after the soil blowoff.

Notice the trench dug around the entire root mass. Typically, the crew uses a line tied to the trunk to swing and mark the edge of trench at the tree’s dripline. If really significant roots appear once the first buckets of soil have been dug, the crew can decide to shift the trench edge outward to save more roots in the blowoff. Alternatively, if no roots are found that far out from the trunk, the excavator can dig closer in to the trunk until roots appear, and the trench placed at that diameter out from the trunk.

Plywood is visible to the left of the photo; soil is blown into the trench for removal, but plenty of soil and dust fly around, and the plywood barriers help contain it, and keep the surrounding site cleaner. The soil pile behind the plywood is what has been excavated to form the trench.

According to Matt, this tree is 20″ dbh, with a 22-24′ wide root mass. The crew blew it off in one day, and moved it about 2,000′ away the next day.

One of the benefits of air tool work like this is the fact that roots become visible, and it becomes clear how a tree grows below the soil surface. The roots here obviously cover a huge area, and their density and branching suggest resilience and vitality.

Notice how much soil remains around the base of the tree. Leaving a slug of soil makes it easier to place the tree level in its new location, at the correct depth. The crew usually blows soil first from the root tips, and works back toward the trunk, always blowing soil toward the trench. The circular track around the tree’s trunk was made by the crew toward the end of the blowout, as they worked their way around the tree. Pigtails of roots are held off the ground with lines tied back to tree branches well-padded with burlap.

Katsura en route to its new home on the UMass campus. Interesting to note how dense and finely branched the tree’s crown is, especially in light of how dense and finely branched the root system is.

Stay tuned for more photos of this tree in the next few months, when we get some followup shots after it has leafed out.